The Post SMTP Mailer/Email Log WordPress plugin before 2.1.7 does not have proper authorisation in some AJAX actions, which could allow high privilege users such as admin to perform blind SSRF on multisite installations for example.

The POST SMTP Mailer WordPress plugin before 2.7.1 does not escape email message content before displaying it in the backend, allowing an unauthenticated attacker to perform XSS attacks against highly privileged users.

The Post SMTP Mailer/Email Log WordPress plugin before 2.1.4 does not escape some of its settings before outputting them in the admins dashboard, allowing high privilege users to perform Cross-Site Scripting attacks against other users even when the unfilteredhtml capability is disallowed.

The POST SMTP Mailer WordPress plugin before 2.5.7 does not have proper CSRF checks in some AJAX actions, which could allow attackers to make logged in users with the managepostmansmtp capability delete arbitrary logs via a CSRF attack.